Because working gives people a sense of worth. Being forced out of something you worked for your whole life because you got older is a horrible feeling, just ask my father. Now, if you are no longer medically qualified or capable, well, that is a whole different story. But you shouldn't be expected to quietly submit and walk off into the sunset because some 19 year old kid wants your job in the nice shiny jet. The young sing this tune now because I guess they feel like they will never get old...but their tone will change as they mature.